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    SubjectRe: copy_from_user() fix
    On Tue, 25 Aug 1998, Jamie Lokier wrote:

    > I bet no applications at all currently check for EFAULT from system
    > calls, unless they're really weird and are doing it to behave _as if_
    > they'd received SIGSEGV. Actually I bet they don't bother because every
    > syscall would need to be wrapped. I'm theorising that this could screw
    > up Wine in some unusual but valid cases.

    I'll take your money. You prove that there are *no* applications
    that check for EFAULT and I'll pay up. Otherwise you pay up. Just
    one condition - we set a time limit :-).

    Seriously though, having looked at good knows how many iBCS traces
    I can tell you that there is plenty of code out there that assumes
    the kernel will give error codes if something is wrong - even when
    they don't explicitly check *what* error occurred. I'm willing to
    bet some of it is EFAULT sensitive.

    (There is code that depends on the *order* that things are checked
    too - even though there is no standard for it)

    > - Only a few applications care whether SIGSEGV is raised or not.

    If you can say that for certain you have spent more on source licenses
    than Bill Gates is worth!

    > I propose EFAULT should be retained, but faulting syscalls should _also_
    > raise SIGSEGV.

    Nononono... If you *must* break compatibility with exisiting systems
    so casually make it a personality flag. Preferably one that is off
    by default unless an application *specifically* asks for it.


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